1. Field of the Invention
This invention relates to a process for the preparation of a sodium sulfate-hydrogen peroxide-sodium chloride adduct and the product of that process.
2. Description of the Prior Art
As hydrogen peroxide adducts of inorganic compounds, there are generally employed sodium percarbonate, sodium perborate and several kinds of phosphate-hydrogen peroxide adducts. These adducts are employed mainly for bleaching, sterilization and the like.
The fields of use of these hydrogen peroxide adducts are frequently limited by the properties of the starting inorganic compounds, and because most of the above-mentioned hydrogen peroxide adducts have a very high alkalinity in aqueous solutions, various limitations are imposed on the uses of these adducts.
It is considered that hydrogen peroxide adducts of neutral compounds such as sodium sulfate can be used for overcoming that disadvantage. However, because the stability of sodium sulfate-hydrogen peroxide adduct is very poor, processes for preparing same and processes of using this hydrogen peroxide adduct have scarcely been reported in the art. Only the results of a few research studies made on properties of this adduct have been reported. Various sodium sulfate-hydrogen peroxide adducts differing in their compositions are formed according to the phase equilibrium relation of Na.sub.2 SO.sub.4 --H.sub.2 O.sub.2 --H.sub.2 O, and they are represented by the general formula Na.sub.2 SO.sub.4.mH.sub.2 O.sub.2.nH.sub.2 O. In general, m is from 0.5 to 2 and n is from 0 to 1.
The stability of such hydrogen peroxide adducts formed by customary concentration methods or the like is very poor. For example, when they are allowed to stand still at 50.degree. C. overnight, a large percentage (more than 20%) of the hydrogen peroxide is lost. Therefore, these hydrogen peroxide adducts cannot be put into practical use. Nevertheless, in view of the fact that sodium sulfate is neutral and non-toxic and is a substance that is available at a low cost and is now used in large quantities as a builder for synthetic detergents, it is considered that if it be possible to prepare a stable sodium sulfate-hydrogen peroxide adduct on an industrial scale, significant advantages will be attained.
It is therefore a primary object of this invention to provide a process for preparing, on an industrial scale, a stable sodium sulfate-hydrogen peroxide adduct.
We have discovered a process according to which a stable sodium sulfate-hydrogen peroxide adduct can be prepared very easily.